Cumulative Layout Shift (CLS) is one of Google’s three Core Web Vitals metrics, measuring how much a page’s visual layout unexpectedly shifts while it’s loading — for example, text jumping down the page as an image or ad loads in above it after the user has already started reading.
Google considers a CLS score under 0.1 to be a good user experience. High CLS scores are frustrating for users and often cause accidental clicks on the wrong element, directly hurting both usability and conversion rates.
Common causes include images or ads without explicitly reserved dimensions, dynamically injected content, and web fonts that cause a visible layout shift when they load in. Fixing CLS typically involves reserving space for these elements in advance, before they finish loading.
CLS improvements are part of our Technical SEO service.